CMOS image sensors may have a column parallel readout using an array of programmable gain amplifiers or PGAs. The array of PGAs reads a row of pixels simultaneously and stores the results in Sample and Hold structures which are typically capacitors. Ideally, the signal being stored by a given column's PGA should be independent of any external conditions such as power or ground supply variation.
When the power supply does show variation, it can induce image artifacts known as “streaking” or “ghosting”. A sample of such an image artifact is shown in FIG. 1. This kind of image artifact can occur when a certain number of PGAs are over saturated, and draw excess power to maintain. The power drawn by the oversaturated PGAs effect the power supply, and thus cause the values of the other PGAs in the same row to deviate. The deviation is shown in FIG. 1 as dark regions, as compared to regions where no PGAs are saturated.